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000 
FXUS63 KGRR 220730
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
330 AM EDT Tue Oct 22 2019

LATEST UPDATE...
Synopsis/Discussion/Marine

.SYNOPSIS...
Issued at 330 AM EDT Tue Oct 22 2019

- Lakeshore Flooding and Beach/Dune Erosion through tonight. 
  (see marine section below)

- Lake effect rain showers lasting from this morning into tonight.

- Multiple chances for additional rain from mid week into the 
  weekend.

&&

.DISCUSSION...(Today through next Monday)
Issued at 330 AM EDT Tue Oct 22 2019

Fall storm system is wrapped up as seen in water vapor imagery 
across Wisconsin. The low is currently around 988mb's over the west 
central part of Wisconsin. As the low lifts northeast today it will 
place Lake Michigan and Western Lower Michigan in a tight pressure 
gradient resulting in windy conditions. Southwest winds of 20-30 mph 
will be common with gusts to 40 mph at times. The strongest winds 
look to occur from late morning through early evening. Will not 
issue any land based wind advisories, but will be maintaining the 
Gale Warning out on the big lake. 

Lake effect rain showers will commence this morning after 12z. The 
lake is roughly around +13C at this time, and as the 0C isotherm at 
850mb rotates through we should see the typical flare up in 
activity. Rain showers will be likely for areas along and west of 
U.S. Highway 131, but all areas will see showers. The most prevalent 
showers will be north and west of Grand Rapids with the least down 
towards Jackson where the SW flow will not reach off Lake Michigan.

Rain showers will continue into tonight, but will wind down late as 
the parent system and deeper moisture lifts away to the north into 
Ontario. Clouds will hang on in most areas tonight, the exception 
being down towards I-94 where we may see some clearing.

Small chances for rain showers will exist from late Wednesday into 
Thursday morning as a surface trough moves through the area. The 
trough will be driven by a shortwave aloft at 500mb's. We currently 
have 30-50 pct chance wording in the forecast for this.

Another small chance for showers along I-94 Thursday night into 
Friday, but there is some model disparity here. Confidence in this 
precipitation is low.

The same goes for Saturday night into Sunday where the Euro brings a 
low with rainfall through the region and the GFS is dry. We are 
splitting the difference and have 20 pops in the forecast for now.



&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 206 AM EDT Tue Oct 22 2019

A very fall like pattern will be in place throughout the course of
the TAF period of 06z Tuesday to 06z Wednesday.

We are currently in the dry slot of a wrapped up fall storm
centered over Wisconsin. What this means is we are mainly clear at
this time (06z). Colder air is beginning to pour across Lake 
Michigan however and the lake clouds and lake generated 
precipitation is about to commence. We are expecting rain showers 
and MVFR ceilings to overspread the area between 12z and 14z this 
morning. A MVFR cloud deck between 1500ft and 2500ft will be in 
place throughout the remainder of the TAF period. The lowest
ceilings around 1500ft are expected in the late morning hours
through the afternoon. Showers will be most prevalent towards Lake
Michigan, or at MKG, GRR and AZO. Conditions will slowly improve
tonight with showers tapering off and ceilings trying to lift to
VFR.

Winds will be a factor today once again out of the southwest
(210-240). Winds speeds will remain in the 10-15 knot range for
the remainder of the night, but jump up considerably around 14z.
15-30 knot winds will be common again today, with gusts between
30-40 knots. Winds will tone down after sunset, especially after
02z to 03z.


&&

.MARINE...
Issued at 330 AM EDT Tue Oct 22 2019

Made no changes to the ongoing Gale Warning and Lakeshore Flood 
Warning headlines. Both will remain in effect until 800am Wednesday. 
Overall no big changes to the forecast. The models have come in with 
a slightly less deep low tonight as opposed to last night. Last night 
the low was forecast to reach the low 980's mb's and tonight it's 
forecast to reach the upper 980's. This may result in slightly less 
wind, but that said BUFKIT overviews are still showing solid 35-40 
knot gales. The time frame of concern is from the current time 
(Gales are now starting to show up in the shoreline obs) through 
roughly 200am tonight. That approximately 24 hour period should 
bring strong winds and large waves to the Lake Michigan shore. 
Again, this event looks a bit worse than last week given the almost 
directly onshore flow and longer duration.

The WaveWatch3 has waves peaking in the 12-14 foot range midday from 
Grand Haven north up the shore through Manistee. The GLERL is around 
the same time for the peak midday, same area, but slightly less at 
11 to 13 feet. Any way you cut it, large waves along a shoreline 
that does not need it. The stretch of shore from Grand Haven north 
through Ludington State Park is most at risk as the WSW flow is 
directly onshore. Last week's event was more along shore and we had 
plenty of damage. 

An item of note is that the Ludington, Muskegon and Cook Nuclear 
(off Bridgman) buoys are all old and may have been pulled from the 
water yesterday for the season. We will be looking at the Port 
Sheldon and South Haven buoys today for wave observations. The 
highest waves will likely be north of both of these buoys. We will 
also be monitoring water levels at Holland and Ludington off the 
NOAA/NOS tides and currents website. Last week both recorded about a 
1 foot storm rise from the push of wind/water that only exacerbates 
the lakeshore flood and erosion problems. More details will be in 
the CFW but suffice it to say we are expecting significant erosion 
today to the dune/bluff and some flooding into beach towns along the 
beach and river mouths.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Lakeshore Flood Warning until 8 AM EDT Wednesday for MIZ037-043-
     050-056-064-071.

LM...Gale Warning until 8 AM EDT Wednesday for LMZ844>849.

&&

$$

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